Year	Percent
1991	70.731
1992	71.053
1993	70.611
1994	71.106
1995	70.769
1996	69.348
1997	69.348
1998	70.022
1999	69.028
2000	67.49
2001	67.564
2002	65.018
2003	64.47
2004	66.772
2005	67.229
2006	70.365
2007	71.203
2008	72.328
2009	72.802
2010	72.673
2011	73.089
2012	72.257
2013	72.041
2014	71.939
2015	70.357
2016	69.47
2017	69.542
2018	69.616
2019	69.682
2020	69.733
2021	69.747
2022	69.766